<!DOCTYPE html>
<html>
<head>
<style>
table { background: white }
col { background: green }
td { color: white }
</style>
</head>
<body onload="runTest()">
 <table>
   <col id="x" span="1">
   <tr>
     <td>One</td>
     <td>Two</td>
     <td>Three</td>
   </tr>
 </table>

 <script>
   function runTest() {
     document.body.offsetWidth;
     document.getElementById("x").setAttribute("span", 2);
   }
 </script>
</body>
</html>
